Early surgery for asymptomatic mitral regurgitation: importance of atrial fibrillation

It remains controversial whether early mitral valve (MV) repair should be performed for severe degenerative mitral regurgitation (MR) without symptoms, left ventricular (LV) dilatation or dysfunction, atrial fibrillation (AF) or pulmonary artery hypertension (PH), even at experienced surgical centers. The study aim was to reconsider the optimal timing of intervention for asymptomatic patients with severe degenerative MR at experienced surgical centers.

Clinical outcomes were reviewed retrospectively for 298 consecutive asymptomatic patients (mean age 57 +/- 12 years) who underwent MV surgery for degenerative MR. The patients were allocated to two groups based on the following comorbid conditions: LVEF < or = 60%, LV end-systolic dimension 40 mm, AF, and PH. Group A comprised 122 patients with none of these conditions, while group B comprised 176 patients with any one of the conditions. The clinical outcomes were compared between the two groups at a mean of 7.0 +/- 4.5 years after surgery.

MV repair had been attempted in all patients, with a success rate of 100%. At 10 years, survival among group B patients was poorer than in group A (93% and 81%, respectively; p = 0.02), and there was a lower freedom from valve-related events (89% and 71%, respectively; p < 0.01). The independent predictors of valve-related events were preoperative AF (hazard ratio 3.34; p < 0.001) and age > 60 years (hazard ratio 2.50; p < 0.01).

Early MV repair is a reasonable option in asymptomatic patients, while preoperative AF may be a more appropriate predictor of an adverse outcome than LV function, as is currently recommended.